the reason why the House of Lords and the House of Commons are separate is to because New Britannia is under personal union, with its own ability to make laws, this is called the House of Governors because its politicians are called Governors, and its head is Governor General, however they share the house of lords with Britannia

Scotland, Wales, Ireland, Cornwall, and Northumbria (the lands of the historic nation of Northumbria) have their own parliaments, as subdivisions of the Houses of commons, however they must meet in london once a year at least.